package showtime.framework.algorithm.crypto{
	　　import flash.utils.ByteArray;
	　　public class Base64 {
		　　private static const BASE64_CHARS:String = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
		　　public static const version:String = "1.0.0";
		　　public static function encode(data:String):String {
			　　// Convert string to ByteArray
			　　var bytes:ByteArray = new ByteArray();
			　　bytes.writeUTFBytes(data);
			　　// Return encoded ByteArray
			　　return encodeByteArray(bytes);
		　　}
		　　public static function encodeByteArray(data:ByteArray):String {
			　　// Initialise output
			　　var output:String = "";
			　　//Create data and output buffers
			　　var dataBuffer:Array;
			　　var outputBuffer:Array = new Array(4);
			　　// Rewind ByteArray
			　　data.position = 0;
			　　// while there are still bytes to be processed
			　　while (data.bytesAvailable > 0) {
				　　// Create new data buffer and populate next 3 bytes from data
				　　dataBuffer = new Array();
				　　for (var i:uint = 0; i < 3 && data.bytesAvailable > 0; i++) {
					　　dataBuffer[i] = data.readUnsignedByte();
				　　}
				　　// Convert to data buffer Base64 character positions and
				　　// store in output buffer
				　　outputBuffer[0] = (dataBuffer[0] & 0xfc) >> 2;
				　　outputBuffer[1] = ((dataBuffer[0] & 0x03) << 4) | ((dataBuffer[1]) >> 4);
				　　outputBuffer[2] = ((dataBuffer[1] & 0x0f) << 2) | ((dataBuffer[2]) >> 6);
				　　outputBuffer[3] = dataBuffer[2] & 0x3f;
				　　// If data buffer was short (i.e not 3 characters) then set
				　　// end character indexes in data buffer to index of '=' symbol.
				　　// This is necessary because Base64 data is always a multiple of
				　　// 4 bytes and is basses with '=' symbols.
				　　for (var j:uint = dataBuffer.length; j < 3; j++) {
					　　outputBuffer[j + 1] = 64;
				　　}
				　　// Loop through output buffer and add Base64 characters to
				　　// encoded data string for each character.
				　　for (var k:uint = 0; k < outputBuffer.length; k++) {
					　　output += BASE64_CHARS.charAt(outputBuffer[k]);
				　　}
			　　}
			　　// Return encoded data
			　　return output;
		　　}
		　　public static function decode(data:String):String {
			　　// Decode data to ByteArray
			　　var bytes:ByteArray = decodeToByteArray(data);
			　　// Convert to string and return
			　　return bytes.readUTFBytes(bytes.length);
		　　}
		　　public static function decodeToByteArray(data:String):ByteArray {
			　　// Initialise output ByteArray for decoded data
			　　var output:ByteArray = new ByteArray();
			　　// Create data and output buffers
			　　var dataBuffer:Array = new Array(4);
			　　var outputBuffer:Array = new Array(3);
			　　// While there are data bytes left to be processed
			　　for (var i:uint = 0; i < data.length; i += 4) {
				　　// Populate data buffer with position of Base64 characters for
				　　// next 4 bytes from encoded data
				　　for (var j:uint = 0; j < 4 && i + j < data.length; j++) {
					　　dataBuffer[j] = BASE64_CHARS.indexOf(data.charAt(i + j));
				　　}
				　　// Decode data buffer back into bytes
				　　outputBuffer[0] = (dataBuffer[0] << 2) + ((dataBuffer[1] & 0x30) >> 4);
				　　outputBuffer[1] = ((dataBuffer[1] & 0x0f) << 4) + ((dataBuffer[2] & 0x3c) >> 2);
				　　outputBuffer[2] = ((dataBuffer[2] & 0x03) << 6) + dataBuffer[3];
				　　// Add all non-padded bytes in output buffer to decoded data
				　　for (var k:uint = 0; k < outputBuffer.length; k++) {
					　　if (dataBuffer[k+1] == 64) break;
					　　output.writeByte(outputBuffer[k]);
				　　}
			　　}
			　　// Rewind decoded data ByteArray
			　　output.position = 0;
			　　// Return decoded data
			　　return output;
		　　}
		　　public function Base64() {
			　　throw new Error("Base64 class is static container only");
		　　}
	　　}
　　}